A. Field of the Invention
The invention relates to optical filters and comprises an optical filter for demonstrating subtractive properties of light.
B. Prior Art
Despite the greatly expanded accessibility of higher education to the public at large, there is an alarmingly increasing ignorance among the public at large with respect to many basic matters of science and technology. Among the fields in which basic understanding is commonly lacking is the field of light, particularly the interaction of light of different colors.
A number of devices are known for demonstrating various properties of light, such as reflection, refraction, and dispersion, among others. Examples of such devices which are intended for common use are simple triangular prisms. Such devices, while simple and thus relatively inexpensive, are of limited appeal after initial use because there is limited or no interaction with each other.
Other devices which are more sophisticated, and thus potentially capable of providing the user with meaningful learning opportunities, are significantly more expensive. Additionally, they are frequently more complicated to use, and thus of limited utility in reaching the general public. More commonly, they appeal only to the smaller segment of the public having a strong interest in science.
Fewer devices are available for teaching the public about the basic interactive properties of light of different colors. Textbook illustrations fail to provide the active, "hands-on"experience that is desirable in learning in the area of science, and many of the physical aids are either too simple and too limited to be of significant value or are too expensive and complex to appeal to more than a limited group. For example, among the simple devices are filters of materials such as cellophane, colored to transmit light of selected colors, to thereby illustrated the subtractive properties of light. Such filters are typically flimsy, easily damaged, and, while inexpensive, not suitable for young children because of their fragility.